Provider backbone bridging or provider backbone bridges (PBB) is an Ethernet-based technology that enables the layering of a network into customer and provider domains with complete isolation between customer and provider Media Access Control (MAC) addresses. This technology is currently being formalized as an IEEE standard identified as IEEE 802.1ah. Provider backbone bridging is implemented by adding a provider backbone header that includes a backbone source address (B-SA), a backbone destination address (B-DA), a backbone VLAN ID (B-VID), and a service instance ID (I-SID). Within a provider backbone bridging domain, packets are forwarded based on backbone media access control (MAC) addresses, loop avoidance is accomplished through Spanning Tree Protocol (STP), and B-VIDs are used for broadcast containment.
When two of Provider Backbone Bridge Networks (PBBN) is connected, they are said to be peer of each other and hence they are peering PBBN networks. This is very common when two different operators interact and customer from one PBBN operator's network wants to communicate with customer of another PBBN operator's network. While communicating, the customer frames are routed as per IEEE standards 802.1Q, 802.1D, 802.1ad, 802.1ah and 802.1Qay. The Ethernet frame header includes a destination address (DA) field, a source address (SA) field, and a VLAN identification (VID) field. When a frame is received by a bridge in first PBBN network, it executes MAC learning by binding the incoming port to the SA of the received frame and storing this information in a filtering database that maintains Forwarding Information (FI). Then the bridge determines whether it has an FI entry associated with the DA of the received frame. If yes, the bridge forwards the frame to a second PBBN network over the specified port only. If there is no associated entry yet, the bridge broadcasts the frame over all of its enabled ports except the incoming port where the frame was received.
In a pure carrier grade network, provisioning in one network should be independent of the values of MAC addresses, I-tag and B-tag values of the peering carrier or service provider network. The carrier or service provider prefers to translate the incoming values or identifiers to his own provisioned values when peering with another service provider. The problem arrives in a data path from one PBBN network to the other because of lacking in the ability to translate the incoming frame at the second PBBN network with their provisioned values. Secondly, MAC address table size of the network is increased on every data path from one node to the other and from one network to the other network.
For the reasons stated above, which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for a method and system for preventing MAC learning while peering Provider Backbone Bridge Network (PBBN).